Method for manufacturing light emitting device

ABSTRACT

A method for manufacturing a light emitting device includes: preparing an intermediate body including a plurality of light emitting elements spaced apart from each other, each of the light emitting elements having a pair of electrodes disposed on the same side, and a covering member covering side surfaces of the light emitting elements while a part of a surface of each of the electrodes is exposed from the covering member, the covering member having a recess between adjacent ones of the light emitting elements; forming a metal layer that continuously covers the surface of each of the electrodes of the light emitting elements and an inner surface of the recess of the covering member; and cutting the metal layer and the covering member at the inner surface of the recess.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Applications No.2016-191246 filed on Sep. 29, 2016 and No. 2017-184703 filed on Sep. 26,2017, the disclosures of which are hereby incorporated by reference inits entirety.

BACKGROUND

The present disclosure relates to a method for manufacturing a lightemitting device.

Light emitting devices including light emitting elements have beenwidely used in the past as a light source in liquid crystal televisionbacklights, lighting fixtures, and the like. As such a light emittingdevice, a light emitting device in which the electrodes of LED elementsserve as connection electrodes for a mother board has been proposed(Japanese Patent Publication No. 2012-227470 A).

SUMMARY

In view of this, it is an object of the present invention to provide amethod for manufacturing a light emitting device with which mounting iseasier while preventing mounting difficulties of the light emittingdevice, which is caused by a relatively small electrode for mounting.

A method for manufacturing a light emitting device according to anembodiment of the present invention includes: preparing an intermediatebody including a plurality of light emitting elements spaced apart fromeach other, each of the light emitting elements having a pair ofelectrodes disposed on the same side, and a covering member coveringside surfaces of the light emitting elements while a part of a surfaceof each of the electrodes is exposed from the covering member, thecovering member having a recess between adjacent ones of the lightemitting elements; forming a metal layer that continuously covers thesurface of each of the electrodes of the light emitting elements and aninner surface of the recess of the covering member; and cutting themetal layer and the covering member at the inner surface of the recess.

With the method for manufacturing a light emitting device according tothe embodiment of the present invention, the light emitting device withwhich mounting is easier can be manufactured.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a schematic plan view showing a step of disposing a lightemitting element on a support according to a method for manufacturing alight emitting device according to an embodiment;

FIG. 1B is a schematic cross-sectional view taken along the line X1-X1′line in FIG. 1A;

FIG. 2A is a schematic plan view showing a step of forming a coveringmember according to the method for manufacturing the light emittingdevice according to the embodiment;

FIG. 2B is a schematic cross-sectional view taken along the line X2-X2′line in FIG. 2A;

FIG. 3 is a schematic cross-sectional view taken showing a step ofexposing the electrodes of a light emitting element from a coveringmember according to the method for manufacturing the light emittingdevice according to the embodiment;

FIG. 4A is a schematic plan view showing a step of forming recesses inthe covering member according to the method for manufacturing the lightemitting device according to the embodiment;

FIG. 4B is a schematic cross-sectional view taken along the line X4-X4′line in FIG. 4A;

FIG. 5A is a schematic plan view showing a step of forming a metal layeraccording to the method for manufacturing the light emitting deviceaccording to the embodiment;

FIG. 5B is a schematic cross-sectional view taken along the line X5-X5′line in FIG. 5A;

FIG. 6A is a schematic plan view showing a step of removing the metallayer from between a pair of electrodes according to the method formanufacturing the light emitting device according to the embodiment;

FIG. 6B is a schematic cross-sectional view taken along the line X6-X6′line in FIG. 6A;

FIG. 7A is a schematic plan view showing a step of cutting the metallayer at the inner surfaces of the recesses according to the method formanufacturing the light emitting device according to the embodiment;

FIG. 7B is a schematic cross-sectional view taken along the line X7-X7′line in FIG. 7A;

FIG. 8 is a schematic side view of a single light emitting deviceaccording to the embodiment;

FIG. 9 is a schematic cross-sectional view showing an example in which alight emitting device shown in FIG. 8 is joined to a mounting board;

FIG. 10 is a schematic side view of a single light emitting deviceaccording to a modified embodiment; and

FIG. 11 is a schematic cross-sectional view showing a method formanufacturing a light emitting device according to the modifiedembodiment.

DESCRIPTION

An embodiment of the present invention will be described below withreference to the appropriate drawings. It should be appreciated,however, that a light emitting device and a method for manufacturing thelight emitting device described below are illustrations to give aconcrete form to technical ideas of the embodiment, and do not limit thepresent invention. In particular, the size, material, shape, relativedisposition and so forth of the components do not limit the technicalscope of the present invention, and are intended to be explanatoryexamples which can sometimes be exaggerated to make the explanationclear. The embodiment described below can apply appropriate combinationsof each configuration and so forth.

The method for manufacturing a light emitting device in this embodimentincludes the steps of preparing an intermediate body including aplurality of light emitting elements that are separated from each otherand have a pair of electrodes on the same side, and a covering memberthat covers the side surfaces of the light emitting elements so thatpart of the surface of the pair of electrodes is exposed and that hasrecesses between the plurality of light emitting elements; forming ametal layer that continuously covers the surfaces of the electrodes ofthe light emitting elements inner surfaces of the recesses of thecovering member; and cutting the metal layer and the covering member atthe inner surfaces of the recesses.

1. Step of Preparing Intermediate Body

First, a step is performed to prepare an intermediate body, whichincludes a plurality of light emitting elements that are separated fromeach other and have a pair of electrodes on the same side, and acovering member that covers the side surfaces of the light emittingelements so that part of the surface of the pair of electrodes isexposed and that has recesses between the plurality of light emittingelements. This step can be performed by the following steps, forexample.

1-1. Disposition of Light Emitting Elements on Support

First, as shown in FIGS. 1A and 1B, a plurality of light emittingelements 2 each having a main light emitting surface Q and a pair ofelectrodes 2 a and 2 b on an electrode formation surface, which is onthe opposite side from the main light emitting surface Q, are disposedon a support 1 so as to be adjacent to each other and face upward.

The light emitting elements 2 include a semiconductor layer including atleast a light emitting layer, and each have the main light emittingsurface Q and the pair of positive and negative electrodes 2 a and 2 bon an electrode formation surface that is on the opposite side from themain light emitting surface Q. Thus using the light emitting elements 2that are individually separated right from the wafer state allows lightemitting devices to be formed at a high yield by selecting thecharacteristics and then using only those light emitting elements thathave the desired characteristics in the manufacture of the lightemitting devices.

The planar shape of the light emitting elements 2 may be circular,elliptical, triangular, quadrangular, pentagonal, hexagonal, or someother such polygonal shape, or the like. Also, the size and thickness ofthe light emitting elements 2 can be appropriately selected. In theEmbodiment 1, for example, the light emitting elements 2 have a planarshape that is rectangular.

A support 1 on which the light emitting elements 2 will be disposed isprepared. The support 1 may be removed before cutting the metal layerand the covering member (discussed below), or may be used as a part ofthe light emitting device by being cut along with the metal layer andthe covering member.

In Embodiment 1, a plurality of the light emitting elements 2 aredisposed adjacent to each other on the support 1 so that the electrodes2 a and 2 b of the light emitting elements 2 face upward, that is, sothat the main light emitting surface Q is in contact with the support 1and the upper surfaces of the electrodes 2 a and 2 b of the lightemitting elements 2 are on the opposite side from the support 1. Thisfacilitates the formation of the metal layer over the electrodes in alater step, and also facilitates the formation of the covering member soas to expose the main light emitting surface Q.

Furthermore, the plurality of light emitting elements 2 are preferablydisposed so that the different poles of the respective light emittingelements 2 are adjacent to each other. More specifically, as shown inFIG. 1A, the plurality of light emitting elements 2 are preferablydisposed so that the positive electrode 2 a of one light emittingelement 2 and the negative electrode 2 b of another light emittingelement 2 are adjacent to each other, and the negative electrode 2 b ofthe one light emitting element 2 and the positive electrode 2 a of theother light emitting element 2 are adjacent to each other.

The spacing of the light emitting elements 2 can be set as desired. Thisspacing affects the thickness of the covering member 3 and the recesses3 a (discussed below). Thus, it is preferable to adjust the spacing sothat the desired thickness of the covering member 3 can be obtained. Forexample, although it depends on the arrangement accuracy of the lightemitting elements 2, the cutting position accuracy in the subsequentdicing step, the configuration of the covering member 3, and the shapeof the recesses 3 a, the spacing of the light emitting elements 2 can beabout 0.1 to 300 μm. This makes it easier to form the metal layer 4 in asubsequent step, and makes it possible to form a covering member 3capable of sufficiently blocking light that leaks out from portionsother than the main light emitting surface Q. Furthermore, the number oflight emitting devices manufactured can be increased, and the lightemitting devices can be manufactured more efficiently.

In laying out the light emitting elements 2 on the support 1, forexample, it is possible to apply an adhesive agent to the support 1 andthe light emitting elements 2 ahead of time, or to use a support 1having an adhesive film and fix the light emitting elements 2 with theadhesive on the support 1. The adhesive agent can be any resin or thelike known in this field. In particular, in the case where the support 1is used as part of the light emitting device 10, it is preferable to usea transmissive resin. In the case where a sticky support 1 is used, thelight emitting elements 2 may be fixed on the support 1 by the tackinessof the support 1. This allows the light emitting elements 2 to beefficiently disposed in just a few steps. A film in which an adhesive isdisposed on a resin, a flat plate such as a ceramic, or the like can beused as the support 1.

1-2. Formation of Covering Member 3

Next, the side surfaces of the light emitting elements 2 are covered soas to expose the upper surfaces of the pair of electrodes 2 a and 2 b,and the covering member 3 having recesses 3 a is formed between thelight emitting elements 2.

1-2-1. Formation of Covering Member 3

In Embodiment 1, the covering member 3 that covers at least the sidesurfaces of the light emitting elements 2 is then formed. Morespecifically, a covering member 3 is formed on the support 1 so as tocontinuously cover the surfaces of the light emitting elements 2disposed on the support 1 other than the portions opposite the support1. Consequently, a covering member 3 for protecting the light emittingelements 2 can be easily formed, and furthermore, in the case where thecovering member 3 has the property of either reflecting or blockinglight, the leakage of light from areas other than the main lightemitting surface Q can be prevented.

As shown in FIGS. 4A and 4B, the covering member 3 is formed so that theelectrodes 2 a and 2 b are exposed from the upper surface of thecovering member 3. The covering member 3 may be formed in a shape suchthat the electrodes 2 a and 2 b are exposed from the outset, or, asshown in FIGS. 2A and 2B, for example, the covering member 3 can beformed at a height that covers the upper surfaces of the electrodes 2 aand 2 b, and a removal portion 3S at the upper part of the coveringmember 3 can be removed by cutting, polishing or the like to expose theelectrodes 2 a and 2 b as shown in FIG. 3. Alternatively, the electrodes2 a and 2 b may be exposed by removing the covering member 3 and theupper portions of the electrodes 2 a and 2 b. The step of exposing theelectrodes 2 a and 2 b will be described in detail below.

The material of the covering member 3 can be one in which a reflectiveor light absorbing substance has been added to a resin or another suchbase material. The covering member can be formed by transfer molding,compression molding, screen printing, potting, spraying, or the like. Inparticular, in order to reliably form the covering member 3 all the wayinto the relatively narrow spaces between the light emitting elements 2,it is preferable to use a molding method featuring a metal mold, such ascompression molding or transfer molding.

The covering member 3 may be formed all at once as discussed above (amode in which part of the formed covering member 3 is removed shall alsobe referred to as forming all at once), or its formation may be brokenup into a number of steps.

1-2-2. Electrode Exposure

In Embodiment 1, after the covering member 3 has covered up to the uppersurfaces of the electrodes 2 a and 2 b, the covering member 3 is thenremoved as shown in FIG. 3, and the upper surfaces of the electrodes 2 aand 2 b of the light emitting elements 2 that were covered by thecovering member 3 are exposed from the surface (upper surface) of thecovering member 3. This brings the electrodes 2 a and 2 b into contactwith the metal layer 4 that will be formed in a subsequent step, andforms electrodes that will supply electricity to the light emittingelements 2.

A method such as grinding, cutting, or etching can be used for theexposure of the electrodes 2 a and 2 b. In order to reduce the decreasein adhesion between the covering member 3 and the metal layer 4 providedin a subsequent step, and between the metal layer 4 and the electrodes 2a and 2 b, in this step the upper surfaces of the electrodes 2 a and 2 band the covering member 3 are preferably made flat so as to besubstantially flush with each other. Grinding is preferable from thisstandpoint, and from the standpoint of improving mass productivity.

The exposure of the electrodes 2 a and 2 b may be performedsimultaneously with the formation of the covering member 3, or may beperformed after the covering member 3 has been formed.

1-2-3. Formation of Recesses

Next, in this embodiment, the recesses 3 a are formed by removing partof the covering member 3. More specifically, as shown in FIGS. 4A and4B, the cover member 3 between the plurality of light emitting elements2 is cut in a direction substantially perpendicularly crossing the mainlight emitting surface Q of the light emitting elements 2. This allowsthe metal layer 4 formed in a subsequent step to be formed all the wayup to the side surfaces of the light emitting device 10.

Removal of the covering member 3 for forming the recesses 3 a can beperformed, for example, by a cutting method that is known in this field,such as blade dicing using a blade, laser dicing, cutter scribing,drilling, or blasting using a mask.

In the case where the light emitting elements 2 disposed on the support1 all have the same shape, it will be easier to form the recesses 3 a inthe covering member 3. Furthermore, since the side surfaces of tworectangular light emitting elements 2 are opposite each other in thisembodiment, the covering member 3 is cut near and along the four sidesof the light emitting elements 2 to easily form the recesses 3 a. In asubsequent step, the covering member 3 and the metal layer 4 can beefficiently cut into individual light emitting devices.

The recesses 3 a may be formed not only by removing part of the coveringmember 3 formed as in this embodiment, but also at the same time as thecovering member 3 is formed. For example, the covering member 3 may beformed in a shape that covers the light emitting elements 2 and also hasthe recesses 3 a in the mold used to form the covering member 3. Therecesses 3 a may be formed either before or after the above-mentionedstep of exposing the electrodes 2 a and 2 b. In the case that therecesses 3 a are formed after the step of exposing the electrodes 2 aand 2 b of the light emitting elements 2, they can be formed whileconfirming the positions of the electrodes 2 a and 2 b of the lightemitting elements 2 with the camera, so this is preferable in terms ofimproving the mass productivity of the light emitting device 10 and theaccuracy of forming the recesses 3 a.

The recesses are preferably provided between the plurality of lightemitting elements 2 at positions adjacent to the electrodes 2 a and 2 bof the light emitting elements. This makes it easier to connect themetal layer 4 provided in the recesses 3 a to the electrodes 2 a and 2 bof the light emitting elements 2.

The shape of the inner surfaces of the recesses 3 a substantiallydetermines the shape of the castellation or the metal layer 4 on theside surfaces of the light emitting device 10 to be manufactured.Therefore, the shape of these inner surfaces should be what is requiredby the characteristics of the light emitting device 10 to bemanufactured and the size.

For example, the depth (the width in the vertical direction in FIG. 4B)of the recesses 3 a can be, for example, about 1% to 99% of the heightof the light emitting device 10. When the depth of the recesses 3 a isincreased, the surface area of the metal layer 4 provided on the sidesurfaces of the light emitting device 10 can be increased, so themounting strength can be increased when the light emitting device 10 ismounted on a mounting substrate. However, in the case where the recesses3 a are made too deep, the end of the metal layer 4 will be closer tothe light emitting surface of the light emitting device 10, so there isthe risk that the solder or other joining member used for mounting willaffect the light emission of the light emitting device. Therefore, thedepth of the recesses 3 a is preferably set to about 20 to 50% of theheight of the light emitting device 10, for example.

The shape of the recesses 3 a in top view may be that of a rectanglethat is longer direction running along the sides of the light emittingelements 2, a circle, or the like. The recesses 3 a are preferablyextended so that the metal layer 4 can be formed from end to end of oneside surface of the light emitting device 10. Using a metal layer 4 suchas this improves the mounting accuracy of the light emitting device 10.

The recesses 3 a may be a single groove extending adjacent to theplurality of light emitting elements 2. This allows the recesses 3 a tobe easily formed by cutting or molding with a metal mold. On the otherhand, a plurality of recesses that are separated from one another in topview may be provided. For instance, the recesses 3 a may be separate butadjacent to each of the plurality of light emitting elements 2.

The width of the recesses 3 a (their length in the lateral direction inFIG. 4B) are preferably provided wide enough that the metal layer 4 canbe easily formed and cut. The side surfaces of the recesses 3 a may beinclined or vertical.

The recesses 3 a should be provided to the portions serving as the sidesurfaces of the light emitting device 10, and in the case where a lightemitting device 10 having a plurality of light emitting elements 2 ismanufactured, the recesses 3 a need not be provided between all of thelight emitting elements 2.

As shown in FIG. 5B, two recesses, or two or more recesses, may beprovided between two light emitting elements 2.

On the other hand, as shown in FIG. 11, just one recess 3 a can beprovided between two light emitting elements 2. This allows the width ofthe recess 3 a to be increased without widening the spacing between thelight emitting elements 2, so it is easier to perform cutting on theinner surfaces of the recesses 3 a (discussed below). Also, the materialof the relatively expensive metal layer 4 formed in the recesses 3 a canbe utilized more effectively, so a less expensive light emitting devicecan be manufactured.

An intermediate body 100 is obtained in this way.

Next, the metal layer 4 is formed so as to continuously cover thesurfaces of the pair of electrodes 2 a and 2 b of the light emittingelements 2 and the inner surfaces of the recesses 3 a of the coveringmember 3 in the intermediate body 100.

2. Formation of Metal Layer

As shown in FIGS. 5A and 5B, the metal layer 4 is formed over thesurface (upper surface) of the light emitting elements of theintermediate body 100 where the electrodes are exposed, and the innersurfaces of the recesses 3 a.

Since the metal layer 4 is used as a mounting terminal for the lightemitting device 10, its structure takes into account the ease ofmounting and adhesion of the light emitting device 10.

Examples of the material of the metal layer 4 include a one or morelayers of gold, silver, nickel, aluminum, rhodium, copper, or an alloyof these. The layer in contact with the intermediate body 100 (the firstlayer of the metal layer) is preferably nickel in order to improve theadhesion. A layer of ruthenium is preferably included in order toprevent diffusion of the mounting solder into the metal layer 4. Also,it is preferable to use gold for the outermost surface because of itshigh corrosion resistance, etc. That is, it is preferable to use alaminated structure of Ni/Ru/Au, starting from the side closer to theintermediate body 100.

The metal layer 4 is preferably thin, and if needed a condition can bethat sufficient bonding strength be ensured when the light emittingdevice 10 is joined to the mounting substrate. The thickness preferablyis such that laser ablation can occur selectively, such as 1 μm or less,with 100 nm or less being even better. Also, a thickness that will allowelectrode corrosion to be reduced, such as 5 nm or more, is preferable.The thickness of the metal layer refers to the total thickness of theplurality of layers in the case where the metal layer is made up of aplurality of laminated layers.

In the case where the metal layer 4 has a laminated structure, thethickness of one layer of the laminated structure can be from 1 to 100nm, for example, with about 15 to 100 nm being preferable.

This metal layer 4 can be formed by ALD, CVD, sputtering, or vapordeposition. Of these, sputtering allows the metal layer 4 to be easilyformed more easily.

In Embodiment 1, first, a single, continuous metal layer 4 is formedover substantially the entire surface of the covering member 3 and theplurality of electrodes 2 a and 2 b. Therefore, as shown in FIGS. 6A and6B, the part of the metal layer 4 that is located so as to connect thepositive and negative electrodes 2 a and 2 b of one light emittingelement 2 is removed. In the case that the part of the metal layer 4does not removed, this part will cause the electrodes 2 a and 2 b toshort-circuit, electrical supply to the light emitting device 10 will bedisrupted, and the light emitting device 10 will be destroyed. The metallayer 4 between the electrodes 2 a and 2 b can be removed in a uniaxialdirection parallel to the electrodes 2 a and 2 b by laser irradiation,etching, or router machining, for example. In particular, laserirradiation allows the metal layer to be removed easily and accuratelyby ablation.

Thus, forming the metal layer 4 by removing part of the metal layer 4provided over substantially the entire surface of one surface of theintermediate body 100 is preferable to forming the metal layer 4 bypatterning with the mask or the like, because it is easier, andtherefore lends itself better to mass production.

The height of the metal layer 4 on the side surfaces of the lightemitting device 10 is about 1% to 99%, and preferably about 10 to 75%,and more preferably about 15 to 50%, of the height of the light emittingdevice 10 from the surface of the light emitting device 10 that isopposite the mounting substrate. The height of the metal layer 4 can becontrolled by means of the depth of the recesses 3 a in the case wherethe metal layer 4 is formed non-selectively on the upper surface of theintermediate body 100.

In this embodiment, since a plurality of light emitting elements 2 aredisposed so that the region between the electrodes 2 a and 2 b of thelight emitting elements 2 is in the form of a single band in plan view,the metal layer 4 in between the positive and negative electrodes 2 aand 2 b of the light emitting elements 2 can be easily removed. In orderto remove the metal layer between the electrodes 2 a and 2 b in astraight line, it is preferable for the disposition of the lightemitting elements 2 on the support 1 to be done in a state of littlepositional deviation. In the case where the light emitting elements 2are arranged with good precision, there will be less of the variance inthe shape of the electrodes that occurs when the metal layer 4 betweenthe electrodes 2 a and 2 b is removed, so the light emitting deviceproductivity and the consistency of quality can be improved.

As long as the metal layer 4 provided on the inner surfaces of therecesses 3 a are electrically connected to the electrodes 2 a and 2 b ofthe light emitting elements 2, the other portion provided to theintermediate body 100 may also be removed. For example, when thecovering member 3 and the metal layer 4 are cut (discussed below), orwhen dicing into the individual light emitting devices 10, the metallayer 4 provided on the upper surface of the intermediate body 100 atthe position to be cut may also be removed. This reduces the generationof metal burrs or debris during cutting, and allows the light emittingdevice 10 to be manufactured stably.

After completion of the light emitting device 10, the portioncorresponding to the peripheral part of the bottom surface of the lightemitting device 10 (the surface called the upper surface in the state ofthe intermediate body 100) may be removed.

Also, with the metal layer 4, the portion connected to one electrode 2 aof a light emitting element 2 and the portion connected to the otherelectrode 2 b may have substantially the same shape or may havedifferent shapes. For example, by making these shapes different fromeach other, they can be used as a mark for discriminating the polarityof the light emitting device 10. This removal can be accomplished bylaser irradiation, or etching, router machining, or the like. Inparticular, laser irradiation allows the removal of the metal layer 4 tobe carried out with good accuracy, so a relatively complicated shape canbe easily formed.

Also, the metal layer 4 may be provided over the entire inner surfacesof the recesses 3 a, or just over a portion thereof.

3. Cutting of Covering Member and Metal Layer

Next, as shown in FIGS. 7A and 7B, the covering member 3 and the metallayer 4 are cut at the inner surfaces of the recesses 3 a.

At this point, the covering member 3 and the metal layer 4 can also becut at the portion without the recesses 3 a.

It is not necessary to perform cutting in all the recesses 3 a. Forexample, in the case where manufacturing a light emitting device thathas a plurality of light emitting elements 2, the light emitting devicemay have the recesses 3 a (and the metal layer 4) in the covering member3 between a plurality of light emitting elements 2, without the recesses3 a disposed between the light emitting elements 2 being cut.

Cutting is performed by any method that allows the covering member 3 andthe metal layer 4 to be cut. For instance, blade dicing using a blade,laser dicing, cutter scribing, or the like can be used.

In this embodiment, since the inner surfaces of the recesses 3 a, whichare each a groove extending adjacent to the light emitting elements 2,are cut using a dicer, cutting can be easily performed.

As shown in FIG. 7B, cutting of the covering member and the metal layermay be accomplished by cutting the recesses 3 a in the approximatecenter of one recess 3 a to split the recess 3 a in two. Also, of theside surfaces of the inner surfaces of the recesses 3 a, the one fartheraway from the light emitting element 2 may be removed. Also, tworecesses 3 a may be cut at once so as to remove the covering memberdisposed between the two recesses 3 a in FIG. 7A. Consequently, thenumber of cuts can be reduced, and cutting can be performedsimultaneously with the removal of the covering member not used in thelight emitting device, so manufacturing can be performed more easily.Also, as shown in FIG. 11, just one recess 3 a provided between twolight emitting elements 2 may be cut, and the two side surfaces of onerecess 3 a may be provided as the side surfaces of two light emittingdevices. This reduces the number of cuts, so manufacturing can beperformed more easily.

In this embodiment, since the covering member 3 is completely cut at thesame time when the covering member 3 and the metal layer 4 are cut atthe inner surfaces of the recesses, it is possible to obtain individuallight emitting devices at the same time (discussed below), and massproductivity can be increased. After the cutting of the covering member3 and the metal layer 4, there may be a formation step or the like, suchas removing the covering member 3 or the metal layer 4.

Obtaining Individual Light Emitting Devices

In this embodiment, as shown in FIGS. 7A and 7B, the covering member 3and the metal layer 4 are also cut at portions other than the recesses 3a to form separation grooves 5 and obtain individual light emittingdevices 10.

As discussed above, when the light emitting elements 2 disposed on thesupport 1 all have the same shape, individual light emitting devices 10can be easily obtained in addition to the formation of the recesses 3 a.In Embodiment 1, since the side surfaces of a plurality of rectangularlight emitting elements 2 are disposed opposite each other, it is easyto cut along the sides of the light emitting element 2, and individuallight emitting devices can be obtained more efficiently.

As discussed above, in the case where individual light emitting devicesare obtained and mounted on the mounting substrate 8 as shown in FIGS. 8and 9, the metal layer 4 that becomes the electrodes of the lightemitting devices 10 can be formed all the way to the surfaces (the sidesurfaces) that are substantially perpendicular to the main lightemitting surface Q. Even though electrodes are not formed on thesurfaces of the electrodes 2 a and 2 b in the same shape as theelectrodes of the mounting substrate 8, mounting can be performed usingthe metal layer 4 on the side surfaces of the light emitting device 10,to manufacture a side-view type of light emitting device 10 that is inwhich the main light emitting surface Q is perpendicular to the mountingsurface of the mounting substrate 8.

This makes it possible to form a light emitting device 10 which can beeasily mounted on the mounting substrate 8.

Thus providing the metal layer 4 used for mounting along the sidesurfaces of the light emitting device 10 allows mounting of the lightemitting device to be performed more easily and accurately. Also, sincesolder fillets are formed on the metal layer 4 on the side surfaces ofthe light emitting device 10 when mounted, it is easy to check themounting of the light emitting device 10, and adhesive strength can beincreased when the mounting board 8 and the light emitting device 10have been mounted. Consequently, this can be used to advantage in acompact light emitting device 10 used in a light source for thebacklight of a liquid crystal display, etc., with which mounting isrelatively difficult, and with which it is difficult to increase thesurface area of the electrodes.

The metal layer 4 is preferably provided over a large surface area onthe bottom surface of the light emitting device 10. For example, it ispreferably provided over 20% to 90%, and more preferably 50% to 80%, ofthe surface area of the bottom surface of the light emitting device 10.This improves the heat dissipation and mounting strength of the lightemitting device 10.

By disposing the side surfaces of the metal layer 4 so as to besubstantially flush with the side surfaces of the light emitting device10, when mounting a plurality of light emitting devices 10 side by side,the above-mentioned effect can be obtained, while the spacing betweenthe light emitting devices 10 can be reduced. This means that the lightemitting devices 10 can be mounted at a higher density.

In this embodiment, the groove recesses 3 a are provided one on eachside of each light emitting element 2, but just one recess may beprovided between adjacent light emitting elements 2. By thus cutting atthe inner surface of a single recess, the metal layer 4 may be formed onthe side surfaces of each of two light emitting devices adjacent to therecesses. This reduces the number of cuts and improves manufacturingefficiency.

In the present embodiment, as shown in FIG. 9, the covering member 3 ofthe light emitting device 10 and the outer surface of the metal layer 4are provided so as to be substantially flush, but as shown in FIG. 10,the covering member 3 of the light emitting device may have an openingon the side surface of the light emitting device, and castellation maybe provided by disposing part of the metal layer 4 in the opening. Thusproviding the metal layer 4 in the opening allows the surface area wherethe solder and the metal layer 4 are bonded to each other to beincreased without raising the height of the metal layer 4, and enhancesthe mounting reliability of the light emitting device. A metal layer 4such as this is formed by widening the recesses 3 a when theintermediate body is prepared, forming the metal layer 4 on the innersurfaces of the recesses 3 a, and then cutting so that part of thebottom surfaces 3 d of the recesses 3 a remains in the light emittingdevice. This opening can be formed by leaving not only the side surfacesbut also the bottom surfaces 3 d of the inner surfaces of the recesses 3a, for example, in the light emitting device when cutting the coveringmember 3 and the metal layer 4.

4. Other Steps

Besides the above steps, a step of forming a wavelength conversionlayer, a step of forming a transmissive layer, or the like may also becarried out as needed, for example.

In the step of forming the wavelength conversion layer, the wavelengthconversion layer that converts the light emitted from the main lightemitting surface Q to the desired wavelength can be formed so as tocover the main light emitting surface Q. The wavelength conversion layercan be, for example, one that contains a wavelength converting materialsuch as a phosphor in a matrix such as a resin or glass. The wavelengthconversion layer can be formed by spraying, printing, coating, affixing,or any other desired manner. A light emitting device with good contrastbetween the light emitting portion and the non-emitting portion (knownas distinguishability) can be formed by also covering the side surfacesof the wavelength conversion layer with the covering member. Dependingon its configuration, the wavelength conversion layer may be formedbefore or after any of the above steps. For example, a sheet composed ofa transmissive resin or the like containing a wavelength convertingmaterial may be used as the support 1, and this support 1 may be used asa wavelength converting layer. Also, a light emitting device with gooddistinguishability can be manufactured by forming in advance awavelength conversion layer whose periphery is surrounded by a frame ofa light-blocking member, and affixing this to the main light emittingsurface prior to formation of the covering member. Also, the coveringmember may be formed after bonding the wavelength conversion layer tothe main light emitting surfaces of the light emitting elements prior toformation of the covering member. The wavelength conversion layer andthe light emitting elements can be easily positioned by bonding the mainlight emitting surfaces of the light emitting elements so as to beopposite each other on the wavelength conversion layer. A silicone resinor another such transmissive adhesive can be used to bond the lightemitting elements to the wavelength conversion layer. This transmissiveadhesive may be provided between the side surfaces of the light emittingelements and the covering member.

The step of forming a transmissive layer is a step of forming atransmissive layer over the light emitting surface of the light emittingdevice (more specifically, the wavelength conversion layer or the mainlight emitting surface Q). Forming a transmissive layer protects thelight emitting surface of the light emitting device. The transmissivelayer can be, for example, resin, glass, etc., that is transmissive.Also, adding a filler or the like improves light extraction and reducestackiness. The transmissive layer can be formed, for example, byspraying, printing, coating, affixing, or any other method desired. Inthe case where the above-mentioned wavelength conversion layer is used,it is preferably provided to the light emitting elements after thewavelength conversion layer and the transmissive layer have been formedin a laminated state first.

Each of the constituent members will be described below.

Light Emitting Elements 2

The light emitting elements 2 can be light emitting diodes, laserdiodes, or the like that are commonly used in this field. For example,it is possible to use a variety of semiconductors such as anitride-based semiconductor (In_(X)Al_(Y)Ga_(1-X-Y)N, 0<X, 0<Y, X+Y<I),a group III-V compound semiconductor such as GaP and GaAs, ZnSe, or agroup II-VI compound semiconductor. The light emitting elements 2 mayhave a substrate for growing the semiconductor layer. Examples ofsubstrates include sapphire and other such insulating substrates, andsubstrates composed of SiC, ZnO, silicon, GaAs, diamond, lithium niobatethat forms a lattice junction with a nitride semiconductor, galliumneodymium, and other substrates composed of an oxide. The substrate maybe removed by laser lift-off method, etc.

Support 1

As mentioned above, the support 1 can be a sheet of resin, ceramic,glass, or the like. From the standpoint of heat resistance, the use of asheet of polyimide resin is particularly favorable.

The planar shape, size, thickness, and so forth of the support 1 can besuitably adjusted depending on the size and number of the light emittingelements 2 to be disposed. In particular, the support 1 is preferably inthe form of a sheet that has a uniform thickness and whose surface isflat, because it will be easier for the light emitting elements 2 to bedisposed stably.

In the case where the support 1 is used as part of the light emittingdevice, it is preferably transmissive, and the transmittance of lightfrom the light emitting elements 2 is preferably at least 60%, morepreferably at least 70%, and even more preferably 80%, with at least 90%being better still.

In particular, in the case where the support 1 is used as part of thelight emitting device, it is preferable to use a resin for the support1. Examples include a support formed from a silicone resin, a modifiedsilicone resin, an epoxy resin, a modified epoxy resin, a phenol resin,a polycarbonate resin, an acrylic resin, a TPX resin, a polynorborneneresin, or a hybrid resin containing one or more of these resins. Ofthese, a silicone resin or epoxy resin is preferable, and a siliconeresin is especially good because of its excellent light resistance andheat resistance.

Furthermore, in the case where the support 1 is used as part of thelight emitting device, and the support 1 is made to contain a wavelengthconversion member that converts the wavelength of light from the lightemitting elements, such as a phosphor and/or a luminescent substance,the result can be used as the wavelength conversion layer of the lightemitting device.

The phosphor and/or luminescent substance can be, for example, ayttrium-aluminum garnet (YAG) phosphor.

The support 1 may contain a filler (such as a diffusing agent or acolorant). Examples include silica, titanium oxide, zirconium oxide,magnesium oxide, glass, phosphor crystals, a sintered phosphor, andsinters of a phosphor and inorganic binder compound.

Covering Member 3

The covering member 3 can be formed, for example, from a materialobtained by adding a reflective or light absorbing substance to a resinbase material. This makes it easier to mold the covering member 3 intothe desired shape. Examples of the resin include silicone resins, amodified silicone resin, an epoxy resin, a modified epoxy resin, anunsaturated polyester resin, a polyimide resin, a modified polyimideresin, a phenol resin, a urethane resin, an acrylate resin, a urearesin, an acrylic resin, a polyphthalamide (PPA), a polyphenylenesulfide(PPS), and a liquid crystal polymer. These may be used alone or incombinations of two or more types. A silicone resin is particularlyfavorable from the standpoint of heat resistance and weather resistance.

A compact light emitting device with which light emitted from somewhereother than the main light emitting surface Q of the light emittingelements can be sufficiently blocked can be formed by setting thethickness of the covering member 3 (the distance from a side surface ofa light emitting element 2 to a side surface of the light emittingdevice 100; D in FIG. 10) to between 10 and 100 μm, for example.

Examples of a reflective or light absorbing substance include ceramics,titanium dioxide, silica dioxide, zirconium dioxide, potassium titanate,alumina, aluminum nitride, silicon nitride, boron nitride, mullite,niobium oxide, zinc oxide, barium sulfate, and various rare-earth oxide(such as yttrium oxide or gadolinium oxide). The reflective or lightabsorbing substance is preferably contained in an amount of about 20 to80 wt %, and more preferably about 30 to 70 wt %, of the total weight ofthe covering member. This ensures that the covering member will havegood strength and light blocking properties.

The light emitting device according to embodiments of the presentinvention can be used for a variety of light emitting devices such as anillumination light source, a light source for various types ofindicators, an in-vehicle light source, a light source for displays, alight source for backlights of liquid crystal displays, a light sourcefor sensors, traffic lights, and the like.

What is claimed is:
 1. A method for manufacturing a light emittingdevice comprising: preparing an intermediate body including a pluralityof light emitting elements spaced apart from each other, each of thelight emitting elements having a pair of electrodes disposed on the sameside, and a covering member covering side surfaces of the light emittingelements while a part of a surface of each of the electrodes is exposedfrom the covering member, the covering member having a recess betweenadjacent ones of the light emitting elements; forming a metal layer thatcontinuously covers the surface of each of the electrodes of the lightemitting elements and an inner surface of the recess of the coveringmember; and cutting the metal layer and the covering member at the innersurface of the recess.
 2. The method for manufacturing a light emittingdevice according to claim 1, wherein the recess is formed by removing apart of the covering member.
 3. The method for manufacturing a lightemitting device according to claim 1, wherein the forming of the metallayer is performed by ALD, CVD, sputtering, or vapor deposition.
 4. Themethod for manufacturing a light emitting device according to claim 1,further comprising removing a part of the metal layer after the formingof the metal layer.
 5. The method for manufacturing a light emittingdevice according to claim 4, wherein the removing of the metal layer isperformed by irradiating the metal layer with a laser.
 6. The method formanufacturing a light emitting device according to claim 1, wherein themetal layer includes Ru.
 7. The method for manufacturing a lightemitting device according to claim 1, wherein the forming of the metallayer includes forming the metal layer having a laminated structure ofNi/Ru/Au.
 8. The method for manufacturing a light emitting deviceaccording to claim 1, wherein the preparing of the intermediate bodyincludes preparing the intermediate body including the covering memberhaving a plurality of recesses including the recess between the adjacentones of the light emitting elements.
 9. The method for manufacturing alight emitting device according to claim 1, wherein the forming of themetal layer includes forming the metal layer to continuously cover innersurfaces of the recesses of the covering member.